OYE Flavoprotein Reductases Initiate the Condensation of TNT-Derived Intermediates to Secondary Diarylamines and Nitrite

Polynitroaromatic explosives such as 2,4,6-trinitrophenol (picric acid) and 2,4,6-trinitrotoluene (TNT) are toxic and recalcitrant environmental pollutants. They persist in the environment due to the highly inactivated π system of their aromatic rings, which are inaccessible to dioxygenases that nor...

Full description

Saved in:
Bibliographic Details
Published in:Environmental science & technology 2008-02, Vol.42 (3), p.734-739
Main Authors: Wittich, Rolf-Michael, Haïdour, Alí, Van Dillewijn, Pieter, Ramos, Juan-Luis
Format: Article
Language:English
Subjects:
Amines - metabolism
Applied sciences
Biodegradation, Environmental
Chromatography, High Pressure Liquid
Condensation
Environmental Processes
Exact sciences and technology
Explosives
Flavoproteins - metabolism
Hydroxylamine - metabolism
NADPH Dehydrogenase - metabolism
Nitrites - metabolism
NMR
Nuclear magnetic resonance
Pollutants
Pollution
Pseudomonas putida
Pseudomonas putida - enzymology
Time Factors
Trinitrotoluene - chemistry
Trinitrotoluene - metabolism
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Polynitroaromatic explosives such as 2,4,6-trinitrophenol (picric acid) and 2,4,6-trinitrotoluene (TNT) are toxic and recalcitrant environmental pollutants. They persist in the environment due to the highly inactivated π system of their aromatic rings, which are inaccessible to dioxygenases that normally initiate the bacterial aerobic catabolism of (nitro-) aromatic compounds. Aside from reductive transformation of nitro side groups to hydroxylamines, trinitroarenes are prone to aromatic ring reductions by some flavin reductases to yield Meisenheimer mono and dihydride complexes. Here we show that the simultaneous accumulation of Meisenheimer complexes and aromatic hydroxylamines derived from TNT gives rise to the condensation of both types of reactive intermediates to secondary diarylamines and nitrite as the end-products of this environmentally relevant reaction sequence. As a consequence, overall mass balances of aerobic biotransformations of TNT become possible for the first time. In our study, the process of TNT activation was enzymatically initiated by the xenobiotic reductase B (XenB)-like flavin reductase of Pseudomonas putida JLR11 and then completed chemically by autodimerization. The structures of the formed end products were unequivocally elucidated by NMR.
ISSN:0013-936X
1520-5851
DOI:10.1021/es071449w